Resistance to first-generation somatostatin receptor ligands does not impair the results of gamma knife radiosurgery in acromegaly.

OBJECTIVE: Gamma knife radiosurgery (GKRS) has proven to be an effective adjuvant treatment for patients with acromegaly. We performed the present study to investigate, which would be the outcome of GKRS, independently on the response to somatostatin receptor ligand (SRL). DESIGN: Retrospective, observational study. PATIENTS: Ninety-six patients with active acromegaly were included. MEASUREMENTS: The cumulative probability of normalisation of insulin-like growth factor 1 (IGF-1) levels after GKRS was assessed by the Kaplan-Meier method. The association of several clinical characteristics with GKRS outcomes was explored with the use of a Cox proportional-hazard model with the relative hazard ratio and 95% confidence interval (CI). RESULTS: Resistance to SRL occurred in 39 of the 96 patients (40.6%). After GKRS, patients resistant to SRL had a 5- and 10-year probability of remission of 40.7% (95% CI: 23.7%-57.7%) and 75.9% (95% CI: 57.9%-93.9%), respectively. Patients responding to SRL had a 5- and 10-year probability of remission of 46.8% (95% CI: 32.2%-61.4%) and 58.1% (95% CI: 41.5%-74.7%), respectively. The difference was not significant (p = .48 by the log-rank test). Multivariate Cox analysis confirmed that the only independent variables associated with GKRS outcome were basal growth hormone (GH; p = .001) and IGF-1 multiple of the upper limit of normal levels before GKRS (p = .013). CONCLUSION: We demonstrate for the first time that the responsiveness to SRL has no effect on the probability to obtain remission of acromegaly after GKRS. The remission of disease occurred more frequently in patients who had lower GH and IGF-1 levels before GKRS.

Factors affecting long-lasting pain relief after Gamma Knife radiosurgery for trigeminal neuralgia: a single institutional analysis and literature review.

Gamma Knife radiosurgery (GKRS) is a well-established safe and effective treatment for trigeminal neuralgia (TN) with high initial success rate (80-90%). Why the pain relief is progressively decreased with time is a matter of considerable debate. To investigate factors related to long-lasting pain relief, the authors conducted a retrospective analysis focusing on anatomical and radiosurgical related parameters, chosen according to literature review. One hundred and twelve patients with classical trigeminal neuralgia and follow-up longer than 12 months were selected from our institutional consecutive series of patients treated by GKRS. Patients were followed for a mean period of 61.5 ± 3.5 months (range, 12-126 months) to evaluate, as endpoints, long-term pain relief and hypoesthesia onset. The median maximum radiation dose was 80 Gy (range 70-90 Gy). Factors related to poor long-term pain relief were prescription dose < 80 Gy (p = 0.038), calibration dose rate < 2.5 Gy/min (p = 0.018), and distance between isocenter and trigeminal nerve emergence > 8 mm (p < 0.001). When analyzing patients who received 80 Gy as maximum dose without any sector blocking, we notice that ID50 < 2.7 mJ was predictive for longer period of pain control (p = 0.043). It was experienced also among patients in which a small volume of the nerve (< 35%) received more than 80% of the maximal dose, compared to those in which a larger volume of the nerve was irradiated with maximal dose (p 0.034). This last result was significant if the shot was 8 mm or less from the pons. Several single-patient anatomical and radiosurgical parameters should be considered to improve GKRS effectiveness.

Intranasal oxytocin as a treatment for obesity: safety and efficacy.

INTRODUCTION: Known for its effect on labor and lactation and on emotional and social functions, oxytocin has recently emerged as a key modulator of feeding behavior and indeed suggested as a potential treatment for obesity. The potential positive effect of oxytocin on both metabolic and psychological-behavioral complications of hypothalamic lesions makes it a promising tool in the management of these conditions. AREAS COVERED: The aim of the present review article is to provide an overview of the mechanism of action and clinical experience of the use of oxytocin in different forms of obesity. EXPERT OPINION: Current evidence suggests a potential role of oxytocin in the treatment of obesity with different causes. Several challenges remain: an improved understanding of the physiological regulation, mechanisms of action of oxytocin, and interplay with other endocrine axes is fundamental to clarify its role. Further clinical trials are needed to determine the safety and efficacy of oxytocin for the treatment of different forms of obesity. Understanding the mechanism(s) of action of oxytocin on body weight regulation might also improve our understanding of obesity and reveal possible new therapeutic targets - as well as promoting advances in other fields in which oxytocin might be used.

Gamma Knife radiosurgery for cluster-tic syndrome unresponsive to medical treatment: illustrative case.

BACKGROUND: Cluster-tic syndrome is a disorder characterized by the coexistence of symptoms related to both cluster headache and trigeminal neuralgia. Etiopathogenesis is not yet well defined. Medical treatment, including drugs for both cluster headache and trigeminal neuralgia, is the first therapeutic choice, whereas more invasive treatments are indicated in the case of pharmacological therapy failure or in the presence of drug side effects. To date, no randomized and/or large cohort trials describing Gamma Knife radiosurgery (GKRS) for cluster-tic syndrome are available, probably due to the syndrome's rarity. OBSERVATIONS: The authors describe the case of a 76-year-old woman with refractory cluster-tic syndrome who underwent GKRS with double target (the retrogasserian portion of the trigeminal nerve and the sphenopalatine ganglion). The Numerical Rating Scale (NRS) of pain and the Barrow Neurological Institute (BNI) pain intensity score before treatment were 7 (up to 10 during paroxysmal pain attacks) and V, respectively. At last follow-up, 24 months after GKRS, the patient had discontinued her pain medications and NRS and BNI pain scores were 1 and I, respectively. No trigeminal sensory disorders were reported. LESSONS: The present case shows that GKRS, in selected cases, could be an effective treatment in patients with refractory cluster-tic syndrome.

Endoscope-Assisted Neuroportal Transcerebellar Approach to the Fourth Ventricle: An Anatomical Study.

BACKGROUND AND STUDY AIMS: Minimally invasive approaches to deep-seated lesions still represent a fundamental issue in modern neurosurgery. Tubular retractors allow to enhance the operability of intraventricular lesions, minimizing the risk of damages to brain parenchyma. Increasing interest for portal devices has been mainly focused on supratentorial pathologies, while transportal approaches in the posterior cranial fossa have been rarely described. In the present study, the authors aimed to investigate the surgical exposure and operability obtained with a microsurgical neuroportal transcerebellar approach targeting the fourth ventricle, assisted by endoscopic exploration. MATERIAL AND METHODS: Six cadaveric specimens were provided for anatomical microsurgical dissection and Vycor ViewSite Brain Access System was used as tubular retractor. Surgical feasibility of the neuroportal transcerebellar approach was demonstrated through a definable and measurable parameter, the operability score. RESULTS: The neuroport provided a surgical corridor away from eloquent structures to target the whole fourth ventricle cavity, preventing injury to cerebellar nuclei and white matter pathways and, potentially, minimizing the risk of surgical morbidity. Maximal operability was reached in the pontomedullary junction and medullary area of the ventricular floor. Transportal endoscopic assistance contributed to a further extension of surgical exposure in blind spots, corresponding to the ipsilateral lateral recess, the uppermost part of the fourth ventricle, and the obex. CONCLUSION: The neuroportal transcerebellar approach represents a viable alternative route to the fourth ventricle, avoiding vermian splitting or subarachnoid dissection of the cerebellomedullary cistern. Endoscopic assistance enhances the exposure of the surgical field and accomplishes a valid instrument for intraventricular orientation to ease microsurgical procedures.

Inverted positioning of Leksell Frame G for very low posterior fossa and brain stem lesions biopsies.

BACKGROUND: The specificity of imaging alone in diagnosing posterior fossa lesions is insufficient, hence the importance of biopsy for diagnostic, therapeutic and prognostic purposes. Concerning the operative technique, many studies have demonstrated the superior safety of stereotactic biopsy over craniotomy and superior accuracy of frame-based systems over frameless ones as far as the posterior fossa is concerned; however versatile, frame-based instruments bear some intrinsic limitations in the positioning of frame in lower lesions mainly in short neck and kyphotic patients. For all these reasons, a more proficient technical bioptic approach to the posterior fossa and lower brainstem is sometimes required. METHODS: In order to obtain a specimen a Leksell System (Elekta®) constituted by the Leksell Coordinate G Frame (Article No: 014611), 4 adjustable posts (Article No: 1006476), 4 reusable screws (Article No: 1006581), an open indicator box (Article No: 1006559), a Leksell Multi-purpose Stereotactic Arc (Article No: 1008174) and a Sedan Needle (Article No: A2430-01) are required. RESULTS: This is a simple and reliable technique to obtain a brainstem/cerebellar specimen maintaining unchanged the know risks of the procedure, as well the morbidity and mortality. We otherwise recommend this procedure to be performed by a team of neurosurgeons trained in stereotaxy. CONCLUSIONS: If meticulously planned, our modified procedure provide a direct and precise access to deep seated areas of the posterior fossa and brainstem and is particularly helpful in those patients with short neck and kyphosis in which is crucial obtain an istopathologic diagnosis in lower posterior fossa.

Anatomic Study on Neuroendoportal Transcortical Approach to Lateral Ventricles.

BACKGROUND: Resection of intraventricular lesions remains a challenge for modern neurosurgery. Endoscopy has provided great advantages in ventricular surgery, even if limited in terms of operability, due to the restricted working channel and impossibility for bimanual surgical manipulation. Tubular approaches have been considered as an option, enabling the use of microsurgical techniques, minimizing violation of brain tissue. The aim of our study was to describe and critically evaluate the use of portal surgery to access lateral ventricles in terms of surgical exposure and operability. METHODS: A microanatomic laboratory cadaver study was conducted with a stepwise description of the surgical technique. The operability score was applied for quantitative analysis of surgical operability, and an illustrative case is reported. RESULTS: Through the anterior approach, the neuroport provides maximal operability at the foramen of Monro and the posterior aspect of the frontal horn, while through the posterior approach maximal operability is achieved in the paratrigonal area. Endoscopic assistance does not affect operability but provides adjunctive exposure in blind spots, as the roof of the frontal horn, the most anterior aspect of the temporal and occipital horn. CONCLUSIONS: Ventricular tubular systems provide adequate visualization, with minimal brain retraction, improving operability as compared with endoscopy. Endoscopic assistance critically widens surgical exposure in blind spots without providing concomitant significant advantage in terms of surgical operability.